A trip to the 700 meters and was built in the latest tunnel in the city of Argentina












While neighbors and opposition legislators denounced irregularities in the largest hydraulic project in the capital, sustained advances to step excavation of one of the two channels provided reliever for the Maldonado stream, that will help prevent flooding in the neighborhoods of Palermo and Villa Crespo, on the axis of the Avenida Juan B. Fair, which will benefit one million residents.

La Nacion ran the 700 meters and built the first tunnel is short, as work begins on the North Coast and was witness, aboard the TBM Valkyria baptized, how the huge drilling machine and remove the earth, while placing the blocks precast concrete more than 30 meters deep.

The first viaduct underground complex stretching from the Costa Salguero (flows into the Rio de la Plata) to the street Niceto Vega, Palermo, began on 21 May; reach the 4.6 miles and would take office in July next year.

"This is a journey to the center of the earth, to quote Jules Verne, defined the Buenos Aires Urban Development Minister, Daniel Chain, as it descended by a staircase of iron and then climbed into a forklift to work to reach the shaft bottom, along with a group of engineers and the nation.
There, the minister explained Chain one reason why the opposition resorted to court to stop the work, contamination of the aquifer Puelche (see separate release). "Here there are 35 meters deep and no more, as they say he (the complaint contends that reached 50 meters). We made modifications to the blueprint for the neighbors could enjoy 12 months prior to this channel," said the official.

These changes would have sued the city an extra outlay of $ 12 million? 20 million dollars to the opposition? of the $ 209 million that the hydraulic project cost to the city, mostly funded by a loan from the World Bank.

Sergio Agostinelli, Secretary of Public Works of the city justified the change in the original plans. "With the new well was improved methodology constructively secured the verticality of the work without error, overall efficiency was achieved in the Tightness; structural problems were eliminated and achieved greater efficiency in the ventilation in the assembly of the tunnellers and evacuation flows. With the original project would have worked in the first stage divers, underwater, with what that entails, "the official said.

End of tunnel

A path consists of an iron structure leads visitors and workers to the end of the tunnel, which is 6.9 meters in diameter, is ventilated and has an artificial light to reveal any detail of the work. They breathe air that is heavier than usual.
"There are between 5 and 10 degrees warmer than outside. And in the future will be full of water," Agostinelli said, explaining the technical aspects of other complex for an ordinary observer.
Something just draws attention in a timely travel site: have seen a sporadic trickle of water on a board. "Is this a loss?" Are consulted specialists. The answer is immediate: "No, this is something to adjust, a trivial issue that has nothing to do with a loss. Imagine the tunnel at this point we have the external water pressure on all the walls. And it's all dry. If had a loss would break everything, "Agostinelli said.
He adds: "Some pools of water that are seen here is due to clay mud and cleaning of tools. Pricked aquifer not Puelche, as they say, nor is there any risk of contamination" .

Night and day without rest

Some 400 workers divided into four shifts (2400 hours used per man-day), work day and night in the relief channel. The TBM Valkyria not rest. 16.50 meters per day progresses linear; 1600 m3 of earth removed, placed 11 rings of precast concrete 1.50 meters; consumes 3500 watts of power, 450 kg fat and 70,000 gallons of water used for cooling ( see graphics).

The walk about six blocks from underground, which spans the track of the airport and Lugones Avenue, ends at the tail of Valkyria, a huge machine that is 105 meters long. The engine noise is deafening at times. On board the machine, to feel how it moves forward, pulling small, perfectly located as precast concrete blocks. "The head is 30 meters and serves as a stopper to the water in front. In the event of an accident, in this structure should get closed operators," said Chain, which shows a sort of closed metal casing.

Both the Minister and the accompanying engineers contend that "there never was a collapse or landslides," nor broke the machine, which is monitored in vivo, not only from the command center set up in Costa Salguero, but also from Italy, where the company Ghella, who carries out the work, monitoring the excavation.

"Today we are working with a 95 percent safety against unforeseen events," Agostinelli said.
This hydro megaprojects? As the city is now the largest program developed in South America? was exposed last year in the 5th Iberoamerican Congress of Engineering, Jalisco, Mexico, among other congresses in Argentina.

Maybe the government reported Macri, was selected for the International Congress of tunneling to be held in 25 to 27 this month in Federal District, Mexico.

"Any expert who knows the subject can verify what you see here: this is perfect relief channel and no environmental contamination by the work or were overpriced in bidding. Are all matters for political reasons," said Chain.

WHY WOMEN CAN NOT WORK?

In the great work of relievers hydraulic Maldonado creek that runs under the avenue casing Juan B. Justo, an old belief is true the world of mining, which states that women can not descend to the tunnels when building, it is considered bad luck. So many tragic cases attest, according to what the workers. In that case, can only do so on December 4, while commemorating the Day of Santa Barbara, the patroness of miners. That's why it asked the nation that traveled through the tunnel to make a reporter and photographer

SOURCE: LA NACION